cmos checksum

I just got a message that said cmos checksum was bad while I was booting up. What does this refer to? My gut instinct says bad battery.

 

That's what I'd look at first.

You'll probably want to check & reset all of the CMOS settings after replacing the battery.

 

Took that advice and ran, literally. I powered down, removed the battery, and ran to Radio Shack. Put the new battery in - all of my settings were still there. I guess I am showing my ignorance in some things when I say that I thought that I would have to redo my BIOS settings.

 

It's actually kinda strange that the CMOS settings didn't change. One of the ways to clear the CMOS settings and revert to the defaults is to remove the battery.

 

There is a jumper on the board to clear that, but I would have thought removing the battery - it was out for at least 15 minutes- would have done the trick. I mean, when the error came up that started all of this I had to reset everything, so having the battery completely out should have done it, too. Stranger things have happened, right? Right? ...

 

Yep, stranger things have happened Taking the battery out does normally clear it.

 

Power

Was it still plugged into the mains? Sometimes that will keep the cmos for a while. Occasionally power takes longer to dissipate than normal. Was there any powered device hooked up to the pc? Although I havent seen any lately, there used to be cmos types that could hold their settings without power for some considerable length of time by design (those were a nightmare if the manufacturer hadnt built in a clear jumper!) Or mabye your board has a capacitance discharge system so power is not cut to the cmos immediately giving you time to change a battery. (rare)

All can cause such an occurence, and there are more besides....

 

I'm kind of surprised that the new battery made the CMOS Checksum error go away. To me, that message means your CMOS is corrupted and would prevent you from booting up. A Clear CMOS usually takes care of it.

 

bATTERY

Could have been a bad battery, outputting voltage or current outside of specifications.

Or youve got a board that eats batteries too fast, if you do get these problems again within a few months from now, get it replaced pronto.